西南小流域洪峰流量估算

Estimation of Peak Flows in Southwest Small Watershed

[目的]准确预测小流域的洪峰流量,为小流域水文应用和水保措施设计提供支撑。[方法]利用重庆万州刘家沟小流域2013—2021年共215次降雨事件数据,采用皮尔逊相关分析的方法,分析了重庆小流域次暴雨洪峰流量与降雨参数和径流参数的相关关系,进而采用线性回归和非线性回归方法,根据降雨径流资料估算了洪峰流量。[结果]研究建立了适用于西南小流域的洪峰流量公式,使用172场降雨事件数据进行参数率定,其模型有效系数为0.85;使用43场降雨事件对模型进行验证,相应的模型有效系数为0.82,结果表明新公式在研究区是可以接受的。[结论]研究建立的洪峰流量公式,能够较好地预测研究流域的洪峰流量,新建公式将为重庆乃至中国西南小流域进行水土保持措施的决策、水土保持工程设施设计和土壤侵蚀评价等提供一定技术基础。

[Objective]The aims of this study are to accurately predict the peak flow at small watershed scale,and to provide support for hydrological application and soil and water conservation assessment.[Methods]The data of 215 rainfall events from 2013 to 2021 were used to analyze effect factors of the peak flow in Liujiagou small watershed,Wanzhou County,Chongqing.The Pearson correlation analysis was performed between peak flow rate and effect factors,including runoff depth,runoff coefficient,rainfall depth,maximum 30-minute rainfall intensity(I 30),and average rainfall intensity.A new peak flow rate equation was developed based on linear regression and nonlinear regression analysis to predict the peak flow rate for small watersheds in Chongqing.The first data set,including 172 storms,was used to develop a new formula for predicting peak flow rate.A second set of data,including 43 storm events,was used to test the new equation.[Results]The peak flow rate was significantly correlated with rainfall,I 30,runoff depth,and runoff coefficient at the 0.01 confidence level.The model efficiency was 0.85 and 0.82 when 172 and 43 rainfall events were used,respectively.[Conclusion]The new equation can provide good accuracy in the small watershed in Chongqing.The new equation will be helpful for the decision-making of soil and water conservation measures,the design of soil and water conservation engineering facilities and the evaluation of soil erosion in Chongqing and even the small watersheds in southwest China.